Control panel displays OH and spa shuts down or will not heat; water may feel very hot near the heater area.

Safety first: Turn off power at the GFCI breaker before opening any equipment compartment. Hot water and live electrical parts can cause serious injury.

• Cool the spa: Remove the cover and allow the water to cool down below 100°F (38°C). Do not run jets until the error clears.
• Check water level: Ensure the water level is above all suction fittings and skimmer openings. Low water can cause localized overheating.
• Clean or remove filters: Take out the MAAX Spas filter cartridges and rinse thoroughly with a garden hose. Try running the spa briefly without filters (with power restored) to see if the OH code clears. If it does, replace clogged filters.
• Bleed air from system: With power off, loosen the union on the MAAX heater or primary circulation pump slightly until water seeps out, then retighten. This removes air locks that can cause heater overheat.
• Inspect circulation: Restore power and verify that the circulation pump is running and there is a steady flow from the circulation return. Weak or no flow indicates a pump or flow restriction issue.
• If OH persists: The high-limit sensor or heater relay on the MAAX control pack may be faulty. Do not bypass safety sensors. Contact a qualified spa technician to test the high-limit sensor and control board.